Most FIRE calculators give you a single number (25 times your spending) and call it a day. This calculator goes further. It runs a year-by-year simulation of your actual retirement: which account you draw from each year, what taxes you owe, how your portfolio grows, and whether your money lasts to your target age.

The FIRE targets adjust for your retirement horizon. Retiring at 35 and planning to 120 means an 85-year retirement, a much longer runway than the 30-year assumption behind the classic 4% rule. This calculator uses research-backed safe withdrawal rates scaled to your actual horizon, then verifies that rate against a full simulation of your specific account mix.

The Roth conversion ladder feature models one of the most powerful tax strategies available to early retirees: converting pre-tax savings to Roth during your low-income bridge years, paying modest taxes now to avoid larger forced distributions later.

What the calculator models

• 2024 federal tax brackets, FICA, and state income tax for all 50 states
• Horizon-adjusted safe withdrawal rates (3.25%–4% depending on retirement length)
• Year-by-year account drawdown: cash → taxable → Roth → traditional, tax-optimized
• Roth conversion ladder with 5-year rule tracking across bridge years
• Required Minimum Distributions starting at age 73 (SECURE 2.0)
• Long-term capital gains tax on the gain portion of taxable withdrawals
• Inflation-adjusted spending with configurable rate
• Coast FIRE, Lean FIRE, FIRE, and Fat FIRE targets in a single view

What it doesn't model

Social Security income, state-specific retirement income exclusions, healthcare costs before Medicare, variable spending strategies (e.g., guardrails), or sequence-of-returns risk via Monte Carlo simulation. These are important factors. Treat this as a starting point, not a complete financial plan.